We have over 12,000 students, from over 100 countries, within one of the safest campuses in the UK


97% of Lancaster students go into work or further study within six months of graduating

Home > Research > Publications & Outputs > Investigation of bandwidth request mechanisms u...
View graph of relations

« Back

Investigation of bandwidth request mechanisms under point-to-multmipomint mode of WiMAX networks

Research output: Contribution to journalJournal article


  • Qiang Ni
  • Alexey Vinel
  • Yang Xiao
  • Andrey Turlikov
  • Tao Jiang
<mark>Journal publication date</mark>2007
<mark>Journal</mark>IEEE Communications Magazine
Number of pages7
<mark>Original language</mark>English


The WiMAX standard specifies a metropolitan area broadband wireless access air interface. In order to support QoS for multimedia applications, various bandwidth request and scheduling mechanisms are suggested in WiMAX, in which a subscriber station can send request messages to a base station, and the base station can grant or reject the request according to the available radio resources. This article first compares two fundamental bandwidth request mechanisms specified in the standard, random access vs. polling under the point-to-multipoint mode, a mandatory transmission mode. Our results demonstrate that random access outperforms polling when the request rate is low. However, its performance degrades significantly when the channel is congested. Adaptive switching between random access and polling according to load can improve system performance. We also investigate the impact of channel noise on the random access request mechanism.